/Engine/Source/Runtime/GeometryCore/Public/TriangleTypes.h
signed area of triangle
static RealType SignedArea ( const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & A, const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & B, const [TVector2](API\Runtime\Core\Math\TVector2)< RealType > & C )